Horizontal load positioner

ABSTRACT

A beam connectable intermediate the ends thereof to a hoist line by spreader cables. One end of the beam adapted for carrying a load and the opposite end of the beam having a plurality of removable counterweights connected thereto for balancing the load to maintain the beam in a horizontal position. In the first form of the invention, the counterweights are fixed with respect to the beam. In the second form of the invention, the counterweights are mounted on a tilt responsive carriage which automatically moves to vary the distance between the counterweights and the fulcrum of the beam to maintain the beam in a horizontal position regardless of the weight of the load.

United States Patent Wheeler [45] July 11, 1972 54] HORIZONTAL LOAD POSITIONER 2,441,026 4/1948 Long ..294/s1 3,075,664 2/1963 Collings [72] Invenmr' gf gl x fiz faag Rute 5 2,721,757 10/1955 Anderson ..294/81 Filed! Julie 1970 Primary Examiner-Even C. Blunk [21] Appl. No: 49,290 Assistant Examiner-J. Kenneth Silverman Attorney-Scofield, Kokjer, Scofield & Lowe Related US. Application Data [63] Continuation-impart of Ser. No. 856,733, Sept. 10, [57] ABSTRACT 1969, abandoned. A beam connectable intermediate the ends thereof to a hoist line by spreader cables. One end of the beam adapted for car- UeS- Cl- R, 1 R [ying a load and the opposite end of the beam having a plurali- [5 l Int. Cl. t ty of removable counterwelghts connected thereto for balanc. [58] Field of Search ..294/67 R, 67 A, 67 AA, 74, ing the load to maintain the beam in a horizontal position I 294/81 81 85; 212/", 18 the first form of the invention, the counterweights are fixed with respect to the beam. In the second form of the invention, [56] References Cited the counterweights are mounted on a tilt responsive carriage UNITED STATES PATENTS which automatically moves to vary the distance between the v counterweights and the fulcrum of the beam to maintain the Moore beam in a horizontal position regardless of the weight of the 2,181,461 11/1939 Moore. .....294/67 1 d 808,719 2/1906 Bray .....294/67 3,343,862 9/1967 Holmes ..294/81 5 Claims, 12 Drawing Figures PKTENTEMLH m2 3,675.961

SHEET 2 BF 3 HORIZONTAL LOAD POSITIONER BACKGROUND AND SUMMARY OF THE INVENTION This application is a continuation-in-part of my copending application Ser. No. 856,733, filed Sept. 10, 1969, entitled Horizontal Hoist Device", now abandoned.

In the construction industry, the problems associated with loading and unloading a building with the aid of a crane or hoist are legion.

During high-rise construction, various supplies are commonly needed at one of the upper stories. A crane or hoist is used to transport the load of supplies from the ground to the level of the building on which they are needed. However, placing a load through an opening such as a window frame or the like is an extremely delicate operation requiring a highly skilled crane operator. The problem is further complicated because any load deposited by a crane must be on dunnage or supporting slats to permit removal of the loading or carrying sling from the load.

After the load is elevated to the proper level, a line is connected to the load and several workmen then grab the line and pull the load into the opening. This causes the crane cable or hoist line to contact the building facade or upper region of the opening. As the load is pulled into the building, the hoist line is bent over the upper edge of the opening and thus the load is raised above the floor level. When it is properly positioned over the dunnage, the crane operator must slacken or drop the load thereon.

Quite obviously this method of operation is an ever-present source of peril to the workmen. Furthermore, it is noted that the hoist line contacting the building facade is a potential source of damage thereto as well as a threat of shearing or weakening the hoist line itself.

When a load is taken from a building, the procedure just described is reversed. Here, the hoist line is connected to the loading sling within the building and the workmen pull on the load to supply a retarding force as the crane operator tightens the hoist line to slide the load out of the opening. Again the hoist line is bent over the upper edge of the opening and likely damages the facing or molding of the building. As the load is slid out the opening, the dunnage is frequently carried along and falls to the ground below. This being the case, additional men are required to stand guard on the ground and to warn others of the falling debris.

The hazard to workmen occasioned by this method of unloading cannot be minimized as there have been instances of men becoming entangled in the rigging and subsequently pulled from the building with the load. Likewise, in addition to the damage to the building and to the hoist line, there is also great potential damage to the load itself. This may happen should the load fall from the sling as it swings out from the building or by otherwise rough treatment as the load is dropped on the dunnage.

That which has been described is the typical sequence of depositing and removing supplies with a hoist line that has been employed in the construction industry for many years. Likewise, the same procedure is used for stocking buildings with heavy or bulky fixtures such as safes, air conditioners, furniture and the like. To my knowledge, there are no devices found in the prior patent art or devices which are commercially available for use with a crane or hoist to eliminate any of the previously mentioned problems. The primary object of this invention is to provide such a device.

More specifically, an object of this invention is to provide a horizontal load positioner connectable to the end of a hoist line for horizontally placing a load within or for horizontally removing a load from an opening in a building in complete safety to workmen and materials. This significant safety feature also yields a substantial reduction in the cost of loading operations by eliminating men previously needed to pull the load into the opening and also by eliminating the guards required to warn others of falling debris. Basically, a building can be loaded or unloaded using only two men. One man is required to operate the crane and an additional man is needed to connect or disconnect the load from the device.

Another object of this invention is to provide a horizontal load positioner for placing a load within or removing a load from an opening in a building without damage to the building or equipment. Such is accomplished without contact of the rigging with portions of the building and thus damage to the building facade and wear on the rigging is virtually eliminated.

Yet another object of the invention is to provide a horizontal load positioner of the character described which departs from the standard loading technique employed for many years in the construction industry. Without the need for men pulling the load into the opening, this device permits the load to penetrate well within the building and then to be gently deposited on the dunnage, thus eliminating potential damage to the load itself.

An additional object of the invention is to provide a horizontal load positioner operable to remove a load from a building without causing dunnage or other debris to fall to the ground.

A further object of the invention is to provide a horizontal load positioner of the character described which effects a loading technique previously unseen in industry whereby a building can be loaded or unloaded in a minimal amount of time.

A further object of the invention is to provide a horizontal load positioner maintainable in a substantially horizontal attitude irrespective of the loaded or unloaded condition of the device. Such is achieved by means of a tilt responsive carriage automatically movable to maintain the device in horizontal equilibrium.

Yet a further object of the invention is to provide a device of the character described which is rugged and durable in construction with great versatility and dependability in operation.

Other and further objects of the invention, together with features of novelty appurtenant thereto, will appear in the course of the following description.

DESCRIPTION OF THE DRAWINGS In the accompanying drawings, which form a part of the specification and are to be read in conjunction therewith, and in which like reference numerals are employed to indicate like parts in the various views:

FIG. 1 is a perspective view of a horizontal load positioner constructed in accordance with one embodiment of the invention and shown in the operating condition of placing a load within an opening of a high-rise construction, a fragmentary view of which is shown;

FIG. 2 is a side elevational view of the load positioner as shown in FIG. 1;

FIG. 3 is a sectional view through the counterweights of the load positioner taken along line 3-3 of FIG. 2 in the direction of the arrows;

FIG. 4 is a side elevational view of a horizontal load positioner constructed in accordance with a second embodiment of the invention and having a movable counterweight carriage;

FIG. 5 is an end view of the counterweight carriage along line 55 of FIG. 4 in the direction of the arrows;

FIG. 6 is a partially sectional view along line 66 of FIG. 4 in the direction of the arrows;

FIG. 7 is a partially sectional view along line 77 of FIG. 4 in the direction of the arrows;

FIG. 8 is an enlarged end view along line 8-8 of FIG. 4 in the direction of the arrows;

FIG. 9 is an enlarged plan view of the counterweight carriage generally along line 99 of FIG. 4 in the direction of the arrows, with the housing of the carriage removed to better illustrate the details of construction;

FIG. 10 is an enlarged fragmentary view along line 10-10 of FIG. 9 in the direction of the arrows;

FIG. 11 is a greatly enlarged, partially sectional, side view of the inner bracket attachment connected to the trolley cable;

FIG. 12 is a greatly enlarged, partially sectional, side view of the outer bracket attachment connected to the trolley cable.

A. FIRST EMBODIMENT Referring to the first embodiment of the invention illustrated in FIGS. 1 through 3, the load positioner, generally designated by the numeral 21, is shown operatively connected to and supported by hoist line 22 of a crane, gin pole, or similar hoisting equipment. The hoist line 22 includes a conventional weight 22a and hook 22b. The load positioner 21 includes an elongate l-beam 23 comprising a vertical portion 23a, lower horizontal portion 23b, and upper horizontal portion 230 on which a pair of spaced coupling plates 24 & 25 are securely attached intermediate the ends of the beam 23. Spreader cables 26 & 27 are connected to the hook 22b of the hoist line 22 by loops 26a 8!. 27a and are connected to the coupling plates 24 & 25 by loops or books 26b & 27b received respectively within eyelets 24a 8:. 250. This type of spanning support provides a measure of horizontal stability to the beam 23 which has a fulcrum or axis of tilt coincident with a downward vertical projection of the hoist line 22.

Connected to one end of the beam 23, hereinafter referred to as the load end 23d, is a load cradle 28 comprising a horizontal member 28a disposed on the upper portion 23c of the beam 23 and asupply platform 28b suspended from the horizontal member 28a by a plurality of slings 28c. As shown in FIGS. 1 and 2, the cradle 28 carries a load 29 which may typically be construction supplies or the like disposed on the. platform 28b.

At the opposite end of the beam 23, hereinafter referred to as the counterweight end 232, a plurality of removable counterweights 30 are connected to the beam 23 by elongate bolts 31 which extend upwardly through bores 30a in the counterweights 30 and upwardly through holes in the beam 23 itself to be secured on the upper portion 23c thereof by nut members 32. The counterweights 30 may be fabricated from any material suitable for this purpose. However, I prefer to fabricate the counterweights 30 from concrete because they can be easily formed at the construction site in any convenient weight and size, used and then discarded when no longer needed. In this manner, one need not undertake the great expense of shipping the counterweights 30 to a construction site since they can be easily and quickly constructed with relatively little expense.

At this point, those skilled in the art will quickly realize the scientific principle underlying this invention is the Lever Arm Rule. The beam 23 itself is a lever having a fulcrum intermediate the coupling plates 24 & 25 and on an imaginary projection of the hoist line 22. From an analysis of the moments about the fulcrum, the product of the distance from the fulcrum to the centroid of the counterweight times the: weight of the counterweight must approximately equal the product of the distance from the fulcrum to the centroid of the load times the weight of the load in order to achieve horizontal. equilibrium of the beam. As an example, suppose that the beam is 20 feet long and is connected to the hoist line to provide a fulcrum or or pivot point equal distance from each end and the weight of the load to be carried is 2,000 pounds. In this case, the weight of the counterweight must equal approximately 2,000 pounds to maintain the beam in a horizontal position. As an additional example, suppose that a 20 foot beam is connected to the hoist line so that the fulcrum is located five feet from the counterweight and thus feet from the load. Here, if a 2,000 pound load is applied, then the total weight of the counterweight must equal about 6,000 pounds in order to maintain the beam in the horizontal position.

In understanding the operation of this first embodiment, FIG. 1 is instructive and the following description is applicable.

Assuming that a load of supplies 29 is needed at one of the upper floors 33a of a high-rise construction 33 as shown in FIG. 1 and must be placed through an opening 33b with the arms aid of a hoist line 22 of suitable hoisting equipment, the proper amount of counterweights 30 to maintain the beam in horizontal equilibrium are first connected to the counterweight end 23:: of the beam 23. Depending upon the weight of the particular load 29, it may also be necessary to adjust the fulcrum closer to the load 29 by connecting the spreader cables 26 and 27 to the eyelets 24a and 25a in each coupling plate 24 and 25 nearest the load 29 or to adjust the fulcrum toward the counterweights 30 by connecting the spreader cables 26 and 27 to the eyelets 24a and 25a in each coupling plate 24 and 25 nearest the counterweights 30. When the load 29 is properly balanced in accordance with the Lever Arm Rule, the horizontal load positioner 21 carrying the load 29 is elevated to the proper floor 330 of the construction 33 with the hoist line 22. Upon reaching this location, the hoisting equipmentmay be turned to cause the load 29 to penetrate the opening 33b. By gradually slackening the hoist line 22, the load 29 is gently deposited on the dunnage (not shown). Thereafter, further slackening of the hoist line 22 permits the counterweights 30 to tilt the beam 23 at an angle and the load cradle 28 can then be disconnected from the load end 23d of the beam. Thus oriented at an angle, the beam 23 is removed from the opening 33b.

With respect to the angle at which the beam 23 is removed from the building 33 after load 29 is disconnected, the spreader cables 26 & 27 serve an important function. If the hoist line 22 was connected to the beam 23 at a single point, disconnecting the load 29 would cause the beam 23 to move to a vertical position thus damaging the superstructure within the opening 33b. However, the spreader cables 26 & 27 prevent this from occurring and permit the beam 23 to tilt only slightly after the load is disconnected. Likewise, cables 26 & 27 of different lengths may be employed to minimize this angle of tilt.

When removing a load 29 from an opening 33b in the construction 33, the reverse of the previously described procedure is used. With the beam 23 oriented at a slight angle, the load end 23d is inserted within the opening 33b and connected to the sling or cradle 28 carrying a load 29. By elevating the hoist line 22, the load 29 is gently lifted from the dunnage causing the beam 23 to shift to a horizontal position and can be removed from the building 33.

The significant safety advantages achieved by loading and unloading operations employing this device are easily recognized. No men are needed to pull the load with brute force into the building. Likewise, since the load is gently lifted from the dunnage rather than slided out the opening, the danger of falling debris is virtually eliminated. These safety advantages also represent substantial savings in both time and manpower.

With this load positioner, a load may be extended well into the opening of a building without causing the hoist line to contact the facade. Therefore, this device not only eliminates damage to the building and rigging, but also minimizes damage to and rough handling of the load itself.

B. SECOND EMBODIMENT The load positioner 21 as previously described has application in a great variety of situations. However, there are situations in which inserting or withdrawing the beam 23 at an angle with respect to the opening is objectionable. In these situations, it is desirable that the beam 23 at all times remain substantially horizontal both in a loaded and unloaded condition. A device having this attribute is provided for the second embodiment of this invention and is now described with reference to FIGS. 4 through 12. The parts of the second embodiment analogous to the parts of the previously described first embodiment are indicated by primed reference numerals.

Referring first to FIG. 4, the load positioner, generally designated by the numeral 21', is shown operatively connected to and supported by hoist line 22' of a crane, gin pole, or similar hoisting equipment. The hoist line 22' includes a conventional weight 22a and hook 22b. The load positioner 21' includes an elongate I-beam 23 comprising a vertical portion 23a, lower horizontal portion 23b, and upper horizontal portion 230 on which a pair of spaced coupling plates 24 & 25 are securely attached intermediate the ends of the beam 23'. Spreader cables 26' & 27' are connected to a gang ring 34 by loops 26a & 27a and are connected to the coupling plates 24 & 25' by loops or hooks 26b & 27b received respectively within eyelets 24a & 25a. The gang ring 34 is supported by the hook 22b of the hoist line 22 Securely welded to the outer portion of one end of the beam 23, hereinafter referred to as the load end 23d (left in FIG. 4), is T-shaped extension stub 35 on which is mounted a swivel load hook 361 As viewed in FIG. 8, the load hook 36 is carried by a shackle 37a and pin 37b received within a bore of the stub 35. The hook 36 includes a hook portion 36a and shank portion 361: swivelly received in a body portion 360. Projecting from the upper end of the body portion 36c are a pair of upright ears 36d through which extend a bolt or pin member 36e coupling the hook 36 to the shackle 37a. The hook 36 is thus operable to support a sling 28' carrying a load 29 as viewed in FIG. 4.

Disposed on the opposite end of the beam 23, hereinafter referred to as the counterweight end 23c, is a movable counterweight carriage, generally designated by the numeral 38. The supporting frame of the carriage 38 includes at each end thereof a pair of vertical members 39a. As viewed in FIG. 5, the vertical members 39a are so spaced to permit the beam 23' to be disposed therebetween and each is connected to a channel member 39b extending from one pair of vertical members 39a to the opposite pair. Likewise, the upright legs of the channel member 39b are of sufficient width to extend upwardly along each side of the beam 23'. Mounted on the channel member 39b and spaced along the length thereof are a plurality of wheels or rollers 40 which are mounted on bolts 40a which are secured by nuts 40b on the exterior surface of the channel member 39b to readily permit a visual safety inspection. As viewed in FIG. 5, the upper surface of the lower portion 23b of the beam 23 provides a track on which the rollers 40 movably support the carriage 38.

At each end of the carriage 38 (FIG. 5), end housing members 390 are connected to the inside surface of the vertical members 39a. These end housing members 39c have a cutout opening 39d through which extends the drive or trolley cable 41, the purpose of which will later be described. On each side of the assembly, wing doors 39e are mounted by piano hinges 39f to upper panels 39g attached to the channel member 3912. In end view, the doors 39s are L-shaped and cooperate with the end housing members 39c to provide a boxlike housing. The doors 39a may be raised to gain access to the interior of the housing with the aid of handles 39h mounted thereon Around the lower periphery of the housing is a rectangular frame 39i constructed of angle iron members and connected to the vertical members 390. On the inner sides of the frame 391', as viewed in FIG. 9, are securely attached angle iron stubs 39j on which rests a floor plate 39k forming a bottom closure for the housing.

Removably secured beneath the frame 39i are a plurality of counterweights supportingly carried by strap supports 42 which are connected by bolts 42a and nuts 42b to each corner of the rectangular frame 391'.

A stop plate 43 (FIGS. 4 and 7) is securely attached, preferably by welding to the end edges of the portions 23a, 23b and 23c, to the outer end of the counterweight end 232 of the beam 23" Outwardly from the fulcrum on the load end 23d is mounted an angular stop plate 44 (FIGS. 4 and 6) on the lower portion 23b of the beam, The previously mentioned trolley cable 41 is interconnected between the stop plates 43 and 44 by attachment means later to be described.

Referring now the power and drive mechanism contained within the housing of the counterweight carriage 38 and operable to move the carriage 38 along the beam 23', reference is made to FIG. 9. The power source for the drive mechanism includes two conventional DC voltage batteries 45 interconnected with a cable 450, grounded by a wire 45b to the frame, and connected by a lead 451: to the electrical circuitry mounted on a panel 46, schematically illustrated. A battery recharger 47 is schematically illustrated and includes a battery condition meter (not shown) to continuously indicate the condition of the batteries 45 to enable one to predict when recharging is necessary. The recharger 47 also includes an electrical receptacle 47a, mounted on the end housing member 39c and having a spring hinged weather cover 47b, to receive an electrical cord for connecting an AC voltage source when recharging becomes necessary.

The drive mechanism includes a direct current compoundwound reversing motor 48 having an output shaft 480 with a sprocket wheel 48b mounted thereon. A continuous chain 49 links the sprocket wheel 48b with a sprocket wheel 50a mounted on the input shaft 50b of a frictionless clutch 50 having an output shaft 50c coupled to the input shaft 51a of a reduction gear box 51. Mounted on the output shaft 511) of the reduction gear box 51 is a cylindrical drum 52 having a spiral groove in the exterior cylindrical surface thereof. The trolley cable 41 is looped around the drum 52 to be received in the spiral groove. The drum 52 also includes circumferential flanges or lips 52a at each end thereof to prevent the cable 41 from slipping off the drum 52.

So constructed, rotation of the output shaft 48a of the motor 48 imparts rotation to the drum 52 which, by virtue of frictional engagement with the trolley cable 41, causes the carriage 38, supported on rollers 40, to move along the counterweight end 23e of the beam. As the motor 48 is operable to selectively rotate in opposite directions, the carriage 38 can thus be moved inwardly or outwardly along the beam 23 in response thereto. The direction of operation and the on-off operation of the motor 48 are controlled by a conventional electrical switching circuit mounted on the electrical panel 46.

As shown in FIG. 10, the electrical panel 46 includes a pair of mercury switches 53 that are oriented at an angle with respect to the horizontal. Preferably, the switches 53 are permanently set in an epoxy resin block 54 which is secured to the panel by bolts 54a. In this manner, the switches 53 need not be adjusted after their initial installation, and likewise, they are not subject to tampering by unauthorized personnel. Thus mounted, the switches 53 are responsive to the tilting of the beam 23 itself. That is, one switch 53 is responsive to the clockwise tilt of the beam 23 with respect to FIG. 4 and when the mercury 53a within that switch 53 interconnects its contact points 53b to close the electrical circuit, the motor 48 is actuated to move the carriage 38 toward the fulcrum of the beam 23' until the beam returns to a horizontal position in which the mercury 53a in the switch 53 no longer interconnects the contact points 53b and thus the electrical circuit is opened and the motor 48 is turned off. Likewise, the other switch 53 is responsive to counterclockwise tilt of the beam 23 with respect to FIG. 4 and controls the on-off actuation of the motor 48 to move the carriage 38 outwardly away from the fulcrum and toward the end of the beam 23.

In this connection, the load positioner 21 is equipped with a manual override control which comprises a push button control box and electrical cord (not shown) that can be connected into the circuitry via electrical receptacle 55, mounted on the end housing member 390 and having a spring hinged weather cover 55a. This control renders the automatic activation of the motor 48 inoperable and permits the operator to independently control the movement of the carriage 38 on the beam 23' as may be needed in emergency situations.

As movement of the carriage 38 is affected by friction between the cylindrical drum 52 and the trolley cable 41, it is important to maintain this cable 41 in tension. In order to maintain the proper tension, it is preferable to spring relieve each end of the trolley cable 41 as illustrated in FIGS. 11 and 12. Referring first to FIG. 12, which illustrates the connection at the outer end of the beam 23', an elongate shaft 56a is slidably received within an opening 43a of the stop plate 43. The inner end of the shaft 56a is afi'lxed with a U-shaped yoke 56b that carries a pin 56c held therein by a cotter pin 560'. The pin 56: extends through the end loop 410 of the trolley cable 41. The outer end of the shaft 560 is threaded to receive an ad justable retension nut 56e which holds a spring seating plug 56f slidably received on the shaft 560. Disposed between the outside face of the stop plate 43 and the plug 56f is a coiled spring 56g encircling the shaft 560. The seating plug 56f includes an inwardly projecting portion substantially the same diameter as the inside diameter of the coiled spring 56g to insure proper seating and alignment of the spring 56 A cylindrical shield 56h encloses the spring 56 shaft 544, plug 56]", and retension nut 56e to prevent damage to such members should that end of the beam 23 come in contact with an object. In addition, the shield 56h also serves to keep the inner end of the spring 56g in proper alignment.

Likewise, as shown in FIG. 11, the inner end of the trolley cable 41 is connected to an elongate shaft 570 having a yoke 57b with a removable pin 57c extending through the end loop 41b of the trolley cable 41 and retained to the yoke 5712 by a cotter pin 57d. The shaft 570 extends through an opening 44a in the inner stop plate 44 and is threaded at the outer end to receive an adjustable retension nut 57e which holds a spring seating plug 57f slidably received on the shaft 570 to retain a coiled spring 57g in proper alignment. As shown in FIG. 4, these members are disposed beneath the beam 23' itself and therefore, damage by contact with other objects is unlikely and a cylindrical shield such as found on the outer end is not required. However, in order to provide a seat for the spring 57g and assure proper alignment thereof, seating member 5711 is attached to the stop plate and has a central bore registering with the opening 440 in the stop plate 44 to slidably receive the shaft 57a. This member 57h also includes a circular raised portion of substantially the same diameter as the inside diameter of the spring 57g to insure proper alignment.

In operation of the load positioner 21' constructed in accordance with the second embodiment, the scientific principle of the previously mentioned Lever Arm Rule is applicable. However, in this embodiment the distance between the fulcrum and the centroid of the counterweight is automatically varied by the moving carriage 38 to maintain the beam 23 in a horizontal position. In this connection and with this versatility, I find it is unnecessary to adjust the fulcrum itself and therefore provide the coupling plates 24' and 25 with single eyelets 24a and 25a.

Assuming that a load 29' is positioned on one story and it is desired to transport the load 29' to an upper story of a highrise construction, the following operational procedure is employed. Since the load positioner 21' is not initially connected to the load 29, one must assume that the carriage 38 is positioned near the fulcrum of the beam 23' and the beam 23 is therefore in a substantially horizontal position.

The hoist operator first causes the load end 2301" of the beam 23' to penetrate the opening in the building after which the load sling 28 can be coupled to the hook 36. As the operator then raises the hoist line 22', the load end 23d of the beam will tilt downwardly under the influence of the load 29 itself. When the angle of the beam 23' reaches a preselected inclination, the mercury 53a in one mercury switch 53 will close the contacts 53b thereof which completes the electrical circuit between the motor 48 and battery power source 45. The motor 48 thus drives the cylindrical drum 52 and the carriage 38 will automatically pull itself along toward the outer end of the beam 23' until the beam 23' is again horizontal and the switch 53 turns off the motor 48. While the carriage 38 is moving along the beam 23', the operator should cease raising the hoist line 22, and by this action of the carriage 38 balancing the load, the load will be lifted from the supporting surface as the beam 23' returns to a horizontal attitude. Thereafter, the operator removes the load positioner 21 carrying the load 29 from the building, elevates it to the proper level, and turns the hoisting apparatus until the load 29' again extends into the opening of the construction. By slackening or lowering the hoist line 22', the load 29' is gently deposited upon the dunnage. As the load is then supported by the dunnage, further lowering the hoist line 22 causes the counterweight end 23a of the beam to tilt downwardly under the influence of the carriage 38 on the outer end thereof. At a preselected angle of tilt, the mercury 53a within the second mercury switch 53 closes the electrical circuit to drive the output shaft 480 of the motor 48 in the opposite direction. This action in turn drives the drum 52 in the opposite direction and the carriage 38 is automatically pulled inwardly toward the center of the beam 23' until the beam 23 returns to a horizontal attitude afterwhich the swivel hook 36 can be disconnected from the load sling 28. While the carriage 38 is moving along the beam 23, the operator should cease lowering the hoist line 22.

According to the Lever Arm Rule, the maximum load which this device will maintain in a horizontal position is determined with the carriage 38 extended to the outer end of the beam 23 as far as possible. In the event the load is too heavy to be successfully balanced by the carriage 38, on attempting to pick up the load, the carriage 38 will automatically move to the outer end of the beam 23' until the vertical members 39a engage the outer stop plate 43. At this point, if the electrical circuit is still closed (that is, the carriage 38 is still attempting to move further outwardly on the beam 23' in order to balance the load), then the slippage of the frictionless clutch 50 prevents damage to the motor 48. In this event, additional counterweights 30, which I prefer to fabricate from concrete in this embodiment also, can be connected beneath the housing by straps 42.

As the carriage 38 moves toward either stop plate 43 or 44, it pulls on the trolley cable 41 in the direction in which it is moving. For example, if the carriage is moving toward stop plate 43 at the outer end of the beam 23', this pull slightly compresses the coil spring 56g via the elongate shaft 560 and the spring 57g associated with the opposite stop plate 43 takes up any slack in the trolley cable 41 and by the collective action of both springs 56g and 57 the trolley cable 41 is kept taunt and in frictional engagement with the cylindrical drum 52.

In connection with the angle of tilt required to activate the carriage 38, I prefer to set the mercury switches 53 in the epoxy block 54 to turn on the motor 48 when the beam 23' is tilted approximately 5 from the horizontal.

Using the principles herein taught, those skilled in the art will recognize several ways in which loads may be balanced by varying the distance between the fulcrum and the counterweight. Such may be accomplished by electrical means as disclosed, by hydraulic means, or by mechanical means using springs or pulleys. However, regardless of the specific construction, this invention fills a void long present in the industry. Loads can now be deposited in or removed from a building without the peril to life and limb and without the damage to equipment and supplies as was common with previous loading techniques.

From the foregoing, it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure.

it will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim:

1. A horizontal load positioner to facilitate depositing a load within or removing a load from an opening in a building with the aid of a hoist line, said positioner comprising:

an elongate beam member;

hoisting tackle connection means connected to said beam member intermediate the ends thereof to suspendingly support said beam member from said hoist line and thereby provide a fulcrum;

a load connection member mounted outwardly from said fulcrum on the first outer end portion of said beam member and adaptable for coupling said load thereto;

a counterweight assembly associated with said beam member outwardly from said fulcrum on the second outer end portion of said beam member; and

load responsive activation means associated with said counterweight assembly to automatically and selectively vary the distance between said fulcrum and said assembly in response to tilting of said beam member from a horizontal attitude whereby said counterweight assembly influences said beam member to return to a horizontal attitude.

2. The load positioner as in claim 1, said counterweight assembly including a plurality of removable counterweights.

3. The load positioner as in claim 1, said counterweight assembly including a carriage having a counterweight removably connected thereto, said carriage mounted on said second outer end portion of said beam member and movable therealong, and said activation means responsive to tilting of said beam member to move said carriage along said beam member whereby to vary the distance between said fulcrum and said carriage and to establish horizontal equilibrium of said beam member.

4. The load positioner as in claim 3, said activation means including:

a self-contained battery power source;

a reversing motor operable to move said carriage along said beam member; and

an electrical circuit interconnecting said power source to said motor, said circuit having a plurality of switches therein operable to selectively activate said motor in response to tilting of said beam member.

5. The load positioner as in claim 1, said hoisting tackle connection means including a pair of spreader cables and a pair of coupling plates attached to said beam member, the upper ends of said cables connected to said hoist line and the lower ends of said cables connected to said coupling plates to provide horizontal stability to said beam member and to provide a fulcrum between said coupling plates. 

1. A horizontal load positioner to facilitate depositing a load within or removing a load from an opening in a building with the aid of a hoist line, said positioner comprising: an elongate beam member; hoisting tackle connection means connected to said beam member intermediate the ends thereof to suspendingly support said beam member from said hoist line and thereby provide a fulcrum; a load connection member mounted outwardly from said fulcrum on the first outer end portion of said beam member and adaptable for coupling said load thereto; a counterweight assembly associated with said beam member outwardly from said fulcrum on the second outer end portion of said beam member; and load responsive activation means associated with said counterweight assembly to automatically and selectively vary the distance between said fulcrum and said assembly in response to tilting of said beam member from a horizontal attitude whereby said counterweight assembly influences said beam member to return to a horizontal attitude.
 2. The load positioner as in claim 1, said counterweight assembly including a plurality of removable counterweights.
 3. The load positioner as in claim 1, said counterweight assembly including a carriage having a counterweight removably connected thereto, said carriage mounted on said second outer end portion of said beam member and movable therealong, and said activation means responsive to tilting of said beam member to move said carriage along said beam member whereby to vary the distance between said fulcrum and said carriage and to establish horizontal equilibrium of said beam member.
 4. The load positioner as in claim 3, said activation means including: a self-contained battery power source; a reversing motor operable to move said carriage along said beam member; and an electrical circuit interconnecting said power source to said motor, said circuit having a plurality of switches therein operable to selectively activate said motor in response to tilting of said beam member.
 5. The load positioner as in claim 1, said hoisting tackle connection means including a pair of spreader cables and a pair of coupling plates attached to said beam member, the upper ends of said cables connected to said hoist line and the lower ends of said cables connected to said coupling plates to provide horizontal stability to said beam member and to provide a fulcrum between said coupling plates. 